chapter 19 mutations and repair

heritable

mutation - a …. change in the genetic material

allelic, foundation, evolutionary, harmful, diseases

• mutations provide … variations

  • positive: mutations are the … for …. change needed for a species to adapt to changes in the environment

  • negative: new mutations are much more likely to be …. than beneficial to the individual and often are the cause of ……

single, base substitution

• gene mutations change the dna sequence of a gene

  • a point mutation is a change in a … base pair

    • it can involve … ….

pyrimidine, pyrimidine, purine, purine

• gene mutations change the dna sequence of a gene

  • a transition is a change of a …. (C,T) to another …. or a …. (A,G) to another ….

pyrimidine, purine

• gene mutations change the dna sequence of a gene

  • a transversion is a change of a …. to a … or vice versa (C to A)

transitions, transversions

• gene mutations change the dna sequence of a gene

  • ….. are more common than ….

addition, deletion

• gene mutations change the dna sequence

  • mutations may also involve the …. or … of short sequences of DNA

substitution, none, none, degeneracy

• consequences of gene mutations

  • type of change: silent

  • mutation in the dna: base …..

  • amino acids altered: …..

  • likely effect on protein function: ……

    • due to … of the genetic code

substitution, one, neutral, inhibitory, AA

• consequences of gene mutations

  • type of change: missense

  • mutation in the dna: base ….

  • amino acids altered: …..

  • likely effect on protein function: …. or ….

    • depends on what the … is changed to

substitution, many, inhibitory

• consequences of gene mutations

  • type of change: nonsense

  • mutation in the dna: base …..

  • amino acids altered: ….

  • likely effect on protein function: ….

addition, deletion, many, inhibitory

• consequences of gene mutations:

  • type of change: frameshift

  • mutation in dna: …. / …..

  • amino acids altered: …..

  • likely effect on protein function: …..

wild type, survive, deleterious, lethal, beneficial, environment, conditional, phenotype, conditions, temperature, sensitive

• mutations can also be described based on their effects on the … …. phenotype

• they are often characterized by their differential ability to …

  • ….. mutations decrease the chances of survival

    • the most extreme are …. mutations

  • ……. mutations enhance the survival or reproductive success of an organism

  • the …. can affect whether a given mutation is either one of these types

• some mutations are ….

  • they affect the … only under a defined set of ….

  • an example is a … - …. mutation

sperm, egg, precursor, offspring, body

• mutations can occur in germ-line or somatic cells

  • germ line mutations are those that occur directly in a …. or … cell, or in one of their …. cells

    • can be passed onto …..

  • somatic mutations are those that occur directly in a ….. cell, or in one of its precursor cells

entire, half, timing, larger, genotypically, genetic mosaic, none

• germ line mutation

  • mutation is found throughout the …… body

  • … of the gametes carry the mutation

• somatic cell mutation

  • the size of the patch will depend on the …. of the mutation

  • the earlier the mutation occurs in development, the ….. the patch

  • an individual who has somatic regions that are …. different from each other is called a …. …..

  • ….. of the gametes carry the mutation

chemical, purine, apurinic, common, pol, randomly, new, covalent, deoxyribose, purine, unstable, amino, cytosine, uracil, base, shape, prior, replication

• causes of spontaneous mutations

  • spontaneous mutations can arise naturally by …. changes

    • 1) depurination - involves the removal of a …. (G or A) from the dna

      • results in an ….. site (very …), if not repaired, dna … will …. insert a …. base

      • the ….. bond between …. and a …. base is ….

        • a mammalian cell loses approximately 10,000 purines every 24 hours

    • 2) deamination - involves the removal of an …. group from ….

      • results in ….

    • 3) tautomeric shift - when a …. temporarily changes …. (keto/enol vs amino/imino forms)

      • can cause a mutation if shape change occurs immediately …. to …..

multi, irregularity, abnormal, removed, normal, synthesized

• dna repair

  • dna repair is a …. step process

    • 1) an … in dna structure is detected

    • 2) the …. dna is ….

    • 3) ….. dna is ….

abnormal, removed, excised, complementary, template, normal

• common types of dna repair systems

  • base excision repair and nucleotide excision repair

    • an …. base or nucleotide is first recognized and …. from the dna

    • a segment of dna in this region is …..

    • then the …. dna strand is used as a … to synthesize a …. dna strand

mismatch, parental, daughter

• common types of dna repair systems

  • mismatch repair

    • similar to excision repair except that the dna defect is a base pair ….. in the dna, not an abnormal nucleotide

    • the mismatch is recognized, and a segment of dna in this region is removed

    • the …. strand is used to synthesize a normal … strand of dna

double, breaks, gap, synthesis, replication, sister

• common types of dna repair systems

  • homologous recombination

    • occurs at …. strand …. or when dna repair damages causes a …. in …. during dna …..

    • the strands of a normal ….. chromatid are used to repair a damaged sister chromatid

double, breaks, proteins, together, rejoined

• common types of dna repair systems

  • nonhomolgous end joining

    • occurs at … strand …

    • the broken ends are recognized by …. that keep the ends ….

    • the broken ends are eventually …..

uv damage, extreme, minimal, skin, 20, tongue, ner

• people with Xeroderma pigmentosum (XP) have mutations in …. … repair genes

  • ….. sensitivity to uv radiation

  • infants burn severely with …. exposure to sunlight

  • 2,000 fold increased risk of …. cancer by age …

  • 100,000 fold increased risk of …. cancer

  • due to mutation in … genes